The transformer has a significant impact on the performance of the short-circuit impedance. Short-circuit impedance, also known as impedance voltage, is an important technical parameter of a transformer, usually expressed as a percentage of the rated voltage.

When the transformer is operating normally, a smaller short-circuit impedance helps reduce voltage drop, thereby improving voltage quality and stability. However, when a short-circuit fault occurs in the transformer, a larger short-circuit impedance is particularly important. This is because a larger short-circuit impedance can effectively limit the magnitude of the short-circuit current, thereby reducing the electromechanical impact on the transformer and protecting it from damage.

In addition, the magnitude of the short-circuit impedance also affects the load distribution of parallel-operated transformers. In parallel-operated transformers, if the short-circuit impedances of the transformers are unequal, their loads cannot be proportionally distributed according to the transformer capacity. Specifically, transformers with smaller short-circuit impedance may be overloaded, while transformers with larger short-circuit impedance may be underloaded. This situation can lead to limited total output power, increased energy loss, and affect the economic operation of the transformer.

Therefore, in the design and manufacturing of transformers, the value of the short-circuit impedance needs to be reasonably selected according to the operating conditions. It is necessary to consider both the voltage drop and voltage quality during normal operation, and the current limitation and transformer protection during short-circuit faults. At the same time, in parallel-operated transformers, it is also necessary to keep the short-circuit impedances of each transformer as equal as possible to ensure that the load can be proportionally distributed according to the capacity, and to achieve the economic operation of the transformer.